Positioning systems are used to estimate the position of a user device (“receiver”) within an environment. Such positioning systems include GNSS positioning systems (e.g. GPS) and non-GNSS positioning systems (e.g. terrestrial positioning systems). GNSS positioning systems and non-GNSS positioning systems transmit positioning signals that are received by a receiver. The received positioning signals are used to generate an estimated position of the receiver (e.g. by estimating the range of travel for each signal, and using those ranges in a trilateration algorithm).
Positioning signals transmitted from non-GNSS transmitters may be generated using PN codes that are selected to allow a receiver to resolve the multipath effects of the positioning signals. The PN codes may be selected to have desirable autocorrelation and cross-correlation properties. Furthermore, chip rates of such positioning signals may be selected such that the bandwidth of the positioning signals is scaled for multipath resolvability. In some instances, an estimated position generated using positioning signals from a non-GNSS positioning system may be more accurate than an estimated position generated exclusively using positioning signals from a GNSS positioning system.
Existing GNSS receiver hardware, while ubiquitous, is not intended for use in determining a position estimate of a receiver using a non-GNSS positioning signal if the code duration and chipping rate of the non-GNSS positioning signal does not relate to that of a GNSS code duration and chipping rate. Unfortunately, adding a non-GNSS positioning module to consumer devices may be impractical or expensive. For this, and for other reasons, it is therefore desirable to process both GNSS positioning signals and non-GNSS positioning signals using the same positioning module hardware (e.g. a GNSS receiver hardware) to allow existing user devices to utilize signaling from non-GNSS positioning systems. Different systems and methods for generating signals from non-GNSS transmitters, and for processing the signals using a GNSS positioning module are described in the disclosure that follows.